Predictors of treatment outcome in acute exacerbation of COPD

Purpose: The goal of this study was to determine the effect of age, severity of lung disease, severity and frequency of exacerbation, choice of an antibiotic and comorbidity on the outcome of treatment for acute exacerbation of COPD (AECOPD). Methods: A retrospective chart analysis of COPD patients at a University VA Medical Center who had been treated with an antibiotic for AECOPD. Severity of AECOPD was defined using Anthonisen's criteria of increased dyspnea, increased sputum volume and increased sputum purulence (Type I-all 3 symptoms (sx), Type II-any 2sx and Type III-any 1sx). Severity of lung disease was stratified using FEV₁% of predicted and home O₂ use. Comorbidity included CHF, coronary artery disease, hypertension, diabetes, liver disease, alcoholism and chronic renal failure. Treat outcome was judged successful when patient had no return visit in 4 weeks for respiratory problem. Failure was defined as change of antibiotics or hospitalization in less than 4 weeks. Results: 107 patients with COPD (mean age ± SD 66.9 ± 9.5 years) experienced 234 exacerbations over 2 years. First-line antibiotics (trimethoprim-sulfa, ampicillin/amoxicillin, erythromycin) were used to treat 79% of all exacerbations. Treatment failure was noted in 12.1% of first exacerbations and 14.7% of all exacerbations, with more than half requiring hospitalization. Predictors of treatment failure included FEV₁<35% (46.4% vs 22.4% p=0.047), home O₂ (60.7% vs 15.6% p<0.0001), frequency of excerbation (3.8 vs 1.6 p<0.001), use of maintenance steroids (32.1% vs 15.2% p=0.052), hx of previous pneumonia (64.3% vs 35.1% p<0.007) and Type I versus Type III (22% vs 7.1% p=0.037) exacerbations. Conclusions: We conclude that severity of lung disease, severity and frequency of excerbation, history of prior pneumonia and use of maintenance steroids had adverse effect on treatment outcome. Surprisingly, age, the choice of antibiotics and comorbidity did not affect the treatment outcome.